Monitoring device for attachment to a surface of a subject

ABSTRACT

The invention provides a monitoring device ( 1 ) for attachment to a surface of a subject. The device comprises a data collector ( 2 ) and a processor ( 3 ) as two separate parts which can be detachably joined such that physiological signals which are detected by the data collector can be transferred to the processor for signal processing and provision of monitoring data. At least one of the data collector and the processor comprises a transducer which can convert the physiological signal to a data signal which can be processed electronically. The data collector is adapted for adhesive contact with a skin surface, and may comprise an adapter ( 6 ) for the detachable attachment of the processor.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.15/364,673, filed Nov. 30, 2016 (now allowed), which is a continuationof U.S. patent application Ser. No. 13/518,780, filed Sep. 10, 2012,(now U.S. Pat. No. 9,521,970), which is a national stage applicationfiled under 35 U.S.C. § 371 of International Patent Application No.PCT/EP2010/070539, filed on Dec. 22, 2010, which claims priority toEuropean Application No. 09180528, filed on Dec. 23, 2009, each of whichis incorporated by reference herein in its entirety.

INTRODUCTION

The present invention relates a monitoring device suitable formonitoring an individual. In particular, the invention relates to adevice which is adhesively attached to the skin of the individual andwhich comprises a processor which can process a physiological signalwhich is received from the individual.

BACKGROUND OF THE INVENTION

WO 2006094513 discloses a micro electronic system predominantly formonitoring physiological or neurological conditions. The system isembedded in a three-dimensional adhesive device which can be attached tothe skin of a mammal. The microelectronic system uses wirelesscommunication and it is useful for measuring ECG (Electro CardioGraphy),EMG (Electro MyoGraphy), EEG (Electro EncephaloGraphy), blood glucose,pulse, blood pressure, pH, and oxygen.

WO 03/065926 discloses a wearable biomonitor with a flexible and thinintegrated circuit. The disclosure includes ways to achieve high comfortof wear by using a thin layer adhesive or pads of adhesive for fixationto the skin.

U.S. Pat. No. 5,054,488 discloses an opto-electronic sensor forproducing electrical signals representative of a physiologicalcondition. The sensors may be attached to the body by a double-sidedpressure sensitive adhesive on a polyester lining.

Rasmus G. Haahr et al. Proceedings of the 5th International Workshop onWearable and Implantable Body Sensor Networks, in conjunction with The5th International Summer School and Symposium on Medical Devices andBiosensors, The Chinese University of Hong Kong, HKSAR, China. Jun. 1-3,2008, relates to a wearable for Wireless continuous monitoring ofphysiological signals in chronically diseased patients.

Rasmus G. Haahr et al. Proceedings of the 29th Annual InternationalConference of the IEEE EMBS Cité Internationale, Lyon, France Aug.23-26, 2007 describes a photodiode for reflectance pulse oximetry inwireless applications of a patch.

SUMMARY OF THE INVENTION

It is an object of embodiments of the invention to provide an improvedsensor for monitoring of an individual.

Accordingly, the invention, in a first aspect, relates to a monitoringdevice suitable for attachment to a surface of a subject, the devicecomprising a data collector and a processor, the data collector having alower surface adapted for adhesive contact with a skin surface of thesubject and adapted for receiving a physiological signal from thesurface, the data collector comprising a transmission structure fortransmitting a monitoring signal which represents the physiologicalsignal to the processor, and the processor being detachably attachableto an upper surface of the data collector and comprising a connectionstructure which, upon attachment, connects to the transmission structurefor receiving the monitoring signal from the data collector, wherein theprocessor comprises an electronic circuit for processing the monitoringsignal to provide monitoring date which relates to a physiological stateof the subject, wherein at least one of the data collector and theprocessor comprises a transducer which can convert the physiologicalsignal to a data signal which can be processed electronically.

Due to the two separate components being detachably attachable to eachother, it becomes possible to use the processor with different datacollectors. As an example, data collectors with different size, shape ortransmission structures could be provided for use with one and the sameprocessor. In another example, the user may reuse the processor afterhaving changed the data collector, e.g. after sport, bathing, or afterother activities which may render the data collector wet, dirty orotherwise worn out.

In the following, the two separate components will be described indetails and subsequently, the interface between the two components andadditional functions will be described.

The main function of the data collector is to adhere to the body of thesubject, to recognize physiologic signals there from, and to transmitthe monitoring signals which represents the physiologic signal to theprocessor. The monitoring signal may be the physiologic signal itself orthe data collector may comprise a transducer for converting aphysiological signal into another form, typically a form which is easierto transfer to the processor and/or a form which is more easilyprocessed by the processor. As it will be described in further detailsin a separate paragraph, the transducer may form part of the datacollector, the processor or both.

Examples of physiological signals relevant in connection with theinvention include an electrical or optical signal such as sternum PPG, apressure signal, a thermal signal or any other signal derivable from thebody of the subject. Such a signal may be significant for aphysiological condition of the subject and in particular for vitalparameters where failure will lead to death, e.g. significant forarterial oxygen saturation (Sp0₂) which can be found by pulse oximetry,or significant for heart beat rate which may be found in various waysincluding pulse oximetry etc, or significant for respiration rate whichagain can be found e.g. by pulse oximetry and oxygen saturation.

In some embodiments in the system according to the present invention thedevice comprises at least one sensor and optionally several differentsensors. The sensor(s) may be configured for measuring one or morephysiological signal selected from electrocardiography (ECG).electromyography (EMG) electroencephalography (EEG), galvanic skinresponse (GSR), phonocardiogram (PCG), arterial oxygen saturation(Sp0₂), muscle activity, emotions, arterial saturation of carbonmonoxide (SpCO) and blood carbon dioxide (CO2), blood pressure (BP),respiration, such as respiration frequency (RF) and/or respirationvolume (RV), heart rate (HR), pulse, bioimpedance, and/or rhythm, heartsounds, respiratory sounds, blood pressure, posture, wake/sleep,orthopnea, heat flux, patient activity, snoring sound or other sounds ofthe subject, and temperature, such as skin temperature (ST), and/or corebody temperature.

In general, the physiological signal will be recognized and picked upfrom the individual by a structure which in the following will bereferred to as “the detecting component”. This component can e.g.include electrodes (polar, bipolar), pressure sensors, needles withelectrodes, accelerometers, photo detectors, microphones, ion specificfield effect transistors (ISFET), a NTC (negative temperaturecoefficient) resistors, band gap detectors, ion membranes, enzymereactors or condensers etc. In particular, the device may comprisecomponents for non-invasive capturing of the physiological signal, e.g.electrodes or optic recognition means. The component could, however,also be for invasive capturing of the physiological signal, e.g. in theform of a needle for taking fluid samples, or a needle containing anelectrode for subcutaneous capturing of an electrical physiologicalsignal.

In addition to the component for capturing of the physiological signal,or as an alternative to the component for capturing of the physiologicalsignal, the data collector may comprise an actuator, i.e. a componentwhich converts energy from one form, typically electrical energy, toanother body sensible form, which can act on the body of the individual.Examples of such actuator components are electrodes, e.g. for neural- orneuro-stimulation, pumps, injection needles, light emission diodes (LED)or other emitters of electromagnetic radiation, pressure wave generatorssuch as loudspeakers, current generators, or chemical synthesizers.Accordingly, the data collector may be designed for two waycommunication of signals to and from the individual.

The data collector may be designed for a specific purpose, e.g. forcollecting electrical signals from a muscle etc. According to thespecific intended use, the data collector may have a shape which matchesa specific location on the body of the subject. Additionally, thedetecting component and the power supply which is optionally included inthe data collector could be designed for the specific signal inquestion.

To ensure correct operation together with the processor, the datacollector may include identification means which identifies the type ofdata collector towards the processor. In this way, the processor mayautomatically adapt to the kind of signals which are monitored, adaptsuitable power schemes for optimal power consumption the specificphysiological signal in question etc.

The data collector may further include identification means whichidentifies the user as such, which identifies a disease, whichidentifies a physical condition to be monitored, or which identifiesother aspects of the user towards the processor. As an example, the datacollector may be made specifically for a physical condition, or for aparticular user. When this dedicated user attaches a processor to thecorrespondingly dedicated data collector, the user, condition etc. isidentified by the processor which can act in a suitable manner, e.g. byprocessing the signal, by using a specific power scheme, by using aspecific sampling frequency or by matching in other ways, the user, thecondition or other identified prerequisite of the monitoring inquestion.

Accordingly, the monitoring device may comprise scheme memory means withspecific data schemes corresponding to a mode of operation, and theidentification means may be adapted to select from these schemes, onemode of operation matching the identification. The scheme memory meansmay form part of the data collector, the data processor or both.

The data collector may also include identification means whichidentifies a recipient who is intended to receive the monitored data,e.g. an e-mail address or web address of a medical practitioner etc.

The data collector may include identification means which identifies aspecific encryption for encrypting the data. When the processor readsthe identification, it may become capable of encrypting the data suchthat only those having corresponding identification or encryptionschemes available can deduct useful information from the processor. Thisfeature may highly increase the safety of the device, and it mayeffectively prevent unauthorized people from getting personal sensitiveinformation. The feature may furthermore ensure that the user onlyreturns to an authorized medical practitioner to have the data analyzedor evaluated.

As an example, a hospital may supply a user with data collectors for aspecific purpose. The user may use a standard processor in combinationwith the received data collectors, and after use, the data could only beevaluated by the hospital who initially handed out the data collectorssince only they are in possession of the matching encryption/decryptioncapabilities.

The data collector may include identification means which identifies anexpected lifetime of the data collector. This feature may effectivelyprevent use of data collectors where the battery or other features havebecome too old to function correctly.

The data collector may include a data storage, e.g. an e-prom or similardevice for storage of electronic data. The data storage may inparticular be accessible by the processor such that the monitored datacan be written on the data storage of the data collector. In this waythe user may return the data collectors, e.g. by traditional mail, tothe medical practitioner who is capable of analyzing the monitoredsignal or generated data.

The data collector may generally include two main components, i.e. abase and an adapter. The base may be made from a flexible tape or patchwith an adhesive on at least the lower surface which is to face towardsthe subject and which is therefore intended to bond the device to thesubject. The adapter forms the interface for the processor and it mayfurther comprise various structures, e.g. a power structure for poweringthe processor, a transducer and/or the transmission structure fortransmitting signals to the processor. Compared with the base, theadapter may be made from a more rigid and less elastically deformablematerial.

The lower surface or base may comprise a gel, e.g. a hydrogel withadhesive properties. The hydrogel may or may not be electricallyconductive. Different forms or formulations of the hydrogel withdifferent properties may be used within the same system or device.

Examples of suitable hydrogels may be obtained from AxelgaardManufacturing Co., Ltd: http://www.axelgaard.com/home.htm or itssubdivision AmGel Technologies; http://www.amgel.com/index.html.

The adhesive or gel may form a transmission passage for thephysiological signal from the individual on which the device is attachedto the detecting component.

In particular, the passage may be a non-interrupted passage from theplace of contact with the individual, e.g. the surface of the skin, tothe detecting component.

The adhesive may form a transmission passage for the physiologicalsignal from the individual to the detecting component. In particular,the passage may be a non-interrupted passage from the place of contactwith the individual, e.g. the surface of the skin, to the detectingcomponent.

In case of detection of e.g. optic or acoustic physiologic signals, sucha non-interrupted passage in one and the same material, namely theadhesive (such as a gel), provides for a minimal loss of signal strengthand quality, such as by preventing reflection, scattering, andrefraction in an interface between materials with different propertiessuch as refractive indices.

The lower surface may comprise an adhesive or gel which amends thephysiological signal, e.g. a gel which modifies an optical signal,filters an electrical signal or dampens an acoustic signal.

In particular, it may be an advantage to use an adhesive, e.g. in formof a hydrogel or similar material with properties ranging from soft andweak jelly-like to hard and tough yet deformable, and if may further bean advantage to use a material with a refractive index in the range of1.01-1.7 e.g. 1.30-1.45, such as 1.34-1.42, In this way, the indexbecomes close to that of average skin whereby reflection of thephysiological signal, be that an acoustic or optic signal, can beprevented or at least reduced.

In one embodiment, the base comprises both an adhesive lower surface andan adhesive upper surface. In this case, the adapter may be fixed to thebase by the adhesive upper surface of the base. In a simple embodiment,the adhesive is electrically conductive, e.g. with a volume resistancein the range of 500-1500 ohm*cm and therefore serves both to conductelectricity and to affix the data collector to the individual.

In other embodiments, the adhesive and detecting component are separatecomponents. In this case, the adhesive may e.g. encapsulate one or moredetecting components on the lower surface of the data collector.

The adapter may project in an upwards direction from the upper surface.An anchoring structure formed on the adapter may cooperate with agripping structure on the processor for the detachable attachment of theprocessor to the data collector.

In one embodiment, the base forms an electrically conductive layertowards the subject and the adapter comprises the transmission structurein the form of electrically conductive paths in a body of anon-conductive material, e.g. pins or wires which are carried by a bodyof a non-conductive material. Herein, non-conductive should beunderstood as “having an electrical conductivity much lower than that ofthe conductive paths”. In this way, the paths form a transmissionstructure adapted to transfer electrical signals. Electricalconnectivity with the processor may also be obtained by use ofconductive brushes etc. or by use of zebra type elastomeric connectorslike those which can be purchased at the Z-axis Connector company, c.f.http://www.zaxisconnector.com or from Fujipoly, c.f. http: fujipoly.com.In zebra wire interconnections, gold wires are at a surface of siliconerubber and ensure good electrical contact while also providing a counterforce for snap locking assembly of the data collector and processor.

To increase flexibility of the device, the transmitters could include anumber of conductive pins which are individually suspended in a body,e.g. such that the pins are movable relative to each other in the body.The body may e.g. be made from an electrically isolating material, e.g.such that the body shields against noise and thereby prevents electricalinterference etc.

The electrical conductivity through the base can be provided e.g. by useof a liquid and electrically conductive gel encapsulated in a thinpatch. In this way, the base will easily adapt to the body shape of thesubject and the conductivity through the base is not influenced bybending or stretching of the base.

In an alternative embodiment, or in combination with the mentionedelectrical paths from the lower surface to the processor, the datacollector may form a transmission structure for transfer of opticalsignals from the subject to the processor. Such a structure may includefiber optics or simply a passage for light or similar electro magneticradiation from the lower surface to the processor. It may furtherinclude a CCD processor or similar electronic means for converting anoptical signal into an electrical signal.

Generally, the transmission structure may combine different signals,e.g. as separate signals, or different signals may be converted e.g.into an optical or electrical signal which is transmitted to theprocessor.

It may be an advantage to include in the data collector, a power sourcefor the processor and other power consumers of the device. In this way,the power source may be optimized to a specific purpose and for aspecific physiologic signal. The power source could be a traditionalbattery.

To ensure good connectivity between the battery in the data collectorand the processor, the battery may be pressed in an upwards directionaway from the lower surface. When the processor is attached to the datacollector, the battery may thereby be pressed against a lower surface ofthe processor.

To press the battery against the processor, the battery may be housed ina body which includes spring force means which provides a spring forceagainst a lower surface of the battery and thereby raises the batterytowards the processor. The body may e.g. form a cup shape with anupwardly curved bottom part which is elastically deformable downwardsand which seeks back in an upwards direction upon deformationdownwardly. Accordingly, the body forms a seat for the battery, and theseat may comprise additional features for securing the battery in place,for providing conductivity between the poles of the battery andcorresponding poles on the processor etc.

The gripping structure could be adapted to destroy the anchoringstructure upon detachment of the data collector from the processor. Inthis way, it is ensured that the data collector is not reused severaltimes, and the data collection quality may thereby be better ensured.

The anchoring structure and the body in which the battery is seatedcould be made in one part, and this same part could also hold electricalconductive pins or in other ways form the mentioned transmissionstructure. For this purpose, this single part may included a shieldingcomponent which protects against radio interference etc and whichthereby reduces or prevents induction of a current in the transmissionstructure, in case it includes electrically conductive paths etc.

Herein, the data which is received by the processor is described as “adata signal”. The data signal could be the physiological signal itself,e.g. an electrical impulse transmitted by a muscle etc. In this case thedata signal can be transmitted directly to the electronic circuit by anelectrically conductive transmission structure.

The monitoring device may comprise filter means for modifying the datasignal. Such modification may include amplification, noise reduction,data comparing or any similar form of data analyzing. The filter meansmay be included in the data collector, in the data processor, or inboth. In particular, it may form part of the transducer.

Alternatively, the data signal could represent a physiological signalwhich is transformed for electrical or optical transmission from theskin of the individual to the electronic circuit. This could be the casee.g. if the physiological signal is a temperature of the skin, a skincolor, a reflectance etc. In such cases, the color, temperature etc istypically transformed into an electrical or optical signal receivable bythe electronic circuit. The transformation of the physiological signalto a data signal, or any later transformation of the data signal into amore processor friendly signal, is carried out by a transducer. In theillustrated embodiment, the transducer forms part of the electroniccircuit or it forms part of software executed in the electronic circuit.

The electrical circuit may comprise one or more application specificintegrated circuits (ASIC), electrical system or subsystem, such as, butnot limited to, printed circuit boards (PCB), flexible printed circuitboards (FPCB), thick film, thin film, or ceramic technologies or thesystem or its components may be separately encapsulated.

To communicate the processed data signal e.g. with an external computersystem, with an alarm central or similar surveillance or monitoringsystem, the device may comprise wireless communication abilities of wellknown kind. This may include Radio Frequency Identification (RFID) tagswhich are commercially available in various sizes, ranges andfunctionality. When the RFID reader applies the appropriate field (e.g.an inductive field) the basic RFID tag return a bit sequence. Thesequence is programmed prior to use. RFID range varies from 1 cm to app.2 meter for passive tags (no power source included) to over 100 metersfor active tags (power source included). More sophisticated RFID tagsavailable have storage components where data can be read or stored.

The wireless communication may form part of the electronic circuit, oroptionally, it may form part of the data collector. As an example, theelectronic circuit or the data collector may include an RF chip and acoil. Suitable forms of the RFID tag is a RFID tag encapsulated in aglass housing, a RFID tag encapsulated in plastic/epoxy (typically pillshaped), a flat RFID tag with coil and a RF chip laminated between 2polyimide layers, or a flat RFID tag with large coil antenna with fewturns printed on or in the adhesive body and with the RF chipinterconnected to the antenna without any furtherprotection/encapsulation.

The wireless communication, in particular in form of a RFID tag, may,when forming part of the data collector, be used to identify either theindividual, or the type of data collector towards the processor. As anexample, the identification may relate to the type of physiologicalsignal to which the data collector pertains, it may relate to the age ofthe data collector or the duration where the data collector was attachedto the skin of the individual, the identity of the individual or othercharacteristics.

In one embodiment, the identification tag is embedded in the adhesivefoil 8.

The communication between the device and other devices may becoordinated in a FFD device, e.g. forming part of the electroniccircuit. The FFD devices may function at any topology and be thecoordinator of the Network, or it may be a coordinator that can talk toany other device. A RFD device is limited to star topology, it cannotbecome a network coordinator, it talks only to a network coordinator andhas very simple implementation. FFDs may be a dedicated networkcoordinator acting as communication Hub, gateway or router within theBody Area Network (BAN) and handling communication with externalunit(s). A communication Hub or gateway may have large storage capacityand store data from the sensor network, and when in proximity withexternal unit or when otherwise appropriate wirelessly transmit thesedata.

In particular for monitoring behavior of the individual, or for makingcombinations between physical activity and other physiological signals,the device may comprise a GPS element, e.g. embedded in the electroniccircuit. The system may e.g. log data related to the position, speed oracceleration of the individual or the limp to which the device isattached.

The electronic circuit could form a gateway comprising storage andcommunication components, a CPU and a battery encapsulated in plasticand working as a dedicated network coordinator for transmission of datato a central unit (CU).

The electronic circuit which forms part of the processor could belocated and protected in a capsule, e.g. a capsule made in one piece,e.g. from a single sheet of metal or made from plastic.

The capsule may form an opening which has a size and shape enabling itto receive at least a portion of the adapter. To protect againstintrusion of dirt and moist etc, the adapter and opening may have shapeswhich matches so well that a gap of at most 1 mm and preferably of lessthan 0.5 mm between the processor and data collector is formed when thetwo parts are assembled.

For ensuring a tight assembly, the adapter may form a plane ledge aroundand upwards projecting tower and the processor may correspondingly forma plane ledge extending circumferentially about the opening.Furthermore, the dimensions may be selected such that the ledge of theprocessor and the ledge of the data collector can come into contact witheach other, or at least become so close that at most 1 mm. or at most0.5 mm between the ledges exist when the tower is inserted in theopening and the gripping and anchoring structures are engaged.

The opening and tower may advantageously be circular such that theprocessor can rotate around the tower, and to make electricalconnectivity between the processor and data collector independent on arotational orientation of one part relative to the other part, theconnectors forming part of the transmission structure may be arrangedsymmetrically around a center of the circular opening and tower.

The transducer may, as mentioned already, form part of the processorand/or of the data collector. Additionally, the transducer may form aseparate component which is attachable to on or both of the processorand data collector, or which may be inserted between the processor anddata collector before the assembly of these two components.

The transducer is designed to convert energy from one form to another.The transducer is typically, but not necessarily, the sensor or sensingpart of the microelectronic sensing system. A transducer may thus beable to convert for example a physical input and the transducer willusually but not necessarily convert this energy into electrical form tobe interpreted by the CPU etc.

Examples of the physical input a transducer may convert is acceleration,chemical/gas, flow, humidity, inertia, capacitance, conductance,conductivity, current, impedance, inductance, pH, resistance, voltage,photo detection, light, magnetism, pressure, angular, linear position,velocity, temperature, sound and mechanical force.

In one embodiment, the transducer is simply constituted by thetransmission structure in combination with electrodes in contact withthe skin of the individual or in combination with an electricallyconductive adhesive.

The processor and/or the data collector may comprise processing meansand corresponding program code which renders the device suitable forvarious monitoring tasks.

As mentioned with regards to the processor and data collector, thesignals and/or monitoring data may be encrypted. For this purpose, thesoftware may include programs for performing such encryption.

In a second aspect, the invention provides a method of monitoring databased on physiological signals received from a subject by use of adevice as already described.

The method comprises attaching a data collector capable of detectingphysiological signals to a surface of the subject and using a separateprocessor which is attached to the data collector for processing thedetected signals and to provide monitoring date which relates to aphysiological state of the subject, wherein at least one of the datacollector and the processor comprises a transducer which can convert thephysiological signal to a data signal which can be processedelectronically.

The subject or the data collector may be identified by the processor byuse of an identification tag forming part of the data collector.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a monitoring device according to the invention;

FIGS. 2 and 3 illustrate exploded views of the monitoring device;

FIGS. 4-6 illustrate details of the monitoring device;

FIG. 7 illustrates a 3D MID on a foil;

FIG. 8 illustrates a possible integration of the optical system andcomponents as part of the processor in the monitoring device;

FIG. 9 illustrates a possible integration of the optical system andcomponents as part of the data collector in the monitoring device; and

FIG. 10 illustrates the top view of two layouts of a printed circuitboard with electro optic components of light emitting diodes (LEDs) andphotodiodes.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a monitoring device 1 with a data collector 2 and aprocessor 3. The data collector has a lower surface 4 provided with abody compatible adhesive, e.g. a hydrogel based adhesive for attachmentof the lower surface to the skin of an individual. The lower surface iselectrically conductive such that a physiological signal can be receivedthough the lower surface. The physiological signal could e.g. be anelectrical signal from a muscle, a color signal or similar opticalsignal received by a photo sensor etc.

The data collector comprises a base forming the lower surface 4 and anopposite upper surface 5. The data collector further comprises anadapter 6 projecting in an upwards direction, indicated by the arrow 7from the upper surface. The adapter forms an anchoring structurecooperating with a gripping structure on the processor and therebyenables detachable attachment of the processor to the data collector.The anchoring and gripping structures are illustrated in FIG. 5.

FIG. 2 illustrates an exploded view of the monitoring device. From thebottom towards the top, the device comprises the following elements:

-   -   8. a foil with double sided adhesive;    -   9. a group of transmitters including in this case 6 individual        transmitters for transmitting an electrical signal from the        foil.    -   10. A body element.    -   11. An electrically conductive ring or bushing inserted in the        body 10 and encircling a battery.    -   12. A battery which is encircled by the ring 11 such that the        ring conducts one of the two phases of the battery.    -   13. A cover foil which is attached adhesively to an upper        surface of the foil 8. The cover foil 13 is preferably made from        a soft, smooth, and bendable material, e.g. from a woven or non        woven fabric.    -   14. A fixing ring for holding the electronic circuit fixed in a        capsule and comprising a gripping structure for holding a        cooperating anchoring structure provided on the data collector.    -   15. An electronic circuit capable of processing the data.    -   16. A capsule housing the electronic circuit.

The foil 8 may have a proximal side facing towards the individual to beadhered to the skin of the individual. The proximal side is providedwith a first adhesive layer and a release liner can be arranged thereon(not shown) for protecting the first adhesive layer until use. The firstadhesive layer may e.g. be a hydrocolloid skin protective adhesivemanufactured by 3M.

A second adhesive layer can be provided on the opposite, distal, side ofthe foil. The purpose of the second adhesive layer is to fix the bodyelement 10 solidly to the foil 8. Accordingly, the second adhesive layermay provide a much stronger bonding than the first adhesive layer.

The cover foil 13 is attached to the second adhesive layer around thebody element 10 to provide a smooth and appealing appearance andoptionally to provide specific characteristics of the device withrespect to bending stiffness, durability, or rigidity. Accordingly, thecover foil 13 may have characteristics regarding stiffness, durability,and/or rigidity which are different from that of the foil.

The body element 10 may be formed in one piece from a non-conductivematerial, e.g. from a plastic material, or formed from a magneticallyshielding material such as a plastic material with embedded metalfibers. The bending stiffness, rigidity, and/or the ability of the bodyelement 10 not to elastically deform may be superior compared to that ofthe foil 8 and cover foil 13.

The body element 10 houses the battery 12 which delivers the electricalpower to the processor but it forms part of the data collector such thata new battery can be provided with every new data collector.Accordingly, the battery may e.g. be of the kind unsuitable forrecharging. Many battery sizes and cell casing exist, including standardcylindrical cells, multi-cell batteries, coin cells, pouch cells andthin film batteries. Any of these could become suitable for the devicedepending on the need for battery capacity and the design of the device.

The body element 10 forms a tower which can be received in the openingin the processor. The body element further forms an anchoring structureto be gripped by the gripping structure of the processor, c.f. FIGS. 5and 6.

The data collector comprises a transmission structure consisting in thiscase of a plurality of individual transmitters 9 which can transmit anelectrical data signal from the lower surface to the processor. Thetransmitters 9 are arranged circumferentially around the body element 10and thus around the battery 12. The body element 10 is made from anon-conductive material and therefore effectively isolates thetransmitters from each other. The body 10 may further be molded with ashielding structure which reduces induction of electrical noise in thetransmitters 9.

Each of the illustrated six transmitters is individually and movablysuspended in the body element 10 which thereby electrically isolates thetransmitter from other transmitters and from the battery 12.

The processor includes the fixing ring 14, the electronic circuit 15,and the capsule 16.

The processor generally processes the received data signal and to do so,it consumes electrical power obtained from a power source.

Further, the processor may be adapted to store the received data signaluntil the time where it is being processed, to store the result of theprocessing of the data signal, and to store software necessary for thetransformation of the received data signal. For this purpose, a storagecomponent may form part of the electronic circuit for storage of theembedded system software and/or storage of data acquired duringoperation of the device. The storage component may be a part of the CPU,a component of its own or an exchangeable storage device such as FLASHRAM that can be removed and exchanged.

FIG. 3 illustrates a side view of the device which is illustrated inFIG. 2. In this view, it is clear that the capsule 16, and thus theprocessor 14, 15, 16 forms a plane ledge 17 extending circumferentiallyabout the opening. The capsule is made in one piece from a blank ofmetal.

FIG. 4 illustrates the capsule 16, the electronic circuit 15, and thebody element 10 including the transmitters 9 seen from below. In thisview, it is clearly visible that the opening in the capsule 16 iscircular. The connection structure and transmission structure areadapted for transmission of the data signal from the data collector tothe processor independently on a rotational orientation of the processorrelative to the data collector. This feature is provided by the 6transmitters 9 which cooperate with the 7 conductive fields 18 whichconstitute the connection structure, and which each has a length whichprovides contact between each transmitter and an individual one of thefields 18 irrespective of the mutual orientation of the connectionstructure and transmission structure.

FIGS. 5 and 6 illustrate a cross section of a gripping structure of theprocessor which is adapted to destroy an anchoring structure of the datacollector upon detachment of the data collector from the processor. Thisfunction will guarantee one-time-use of the data collector and thusimprove the reliability of the device.

FIG. 7 illustrates the transmission structure made with 3D MID whichallows integration of mechanical and electrical functions in a mouldedpart. In a first injection cycle, moulding material is injected onto thefoil 8 to form the body element 10 directly on the foil. In this stagethe body element is moulded with channels which are filled with anelectrically conductive polymer in a second injection cycle. In thesecond injection cycle, the conductive polymer is injected into thechannels and out onto the foil 8 on those locations where there iscontact down through the foil into the conductive gel and/or conductiveadhesive which comes in contact with the skin of the subject.

EXAMPLE

The following is an example of further details which may be included ina device according to the invention.

FIG. 8: The FIG. illustrates a possible integration of the opticalsystem and components in the monitoring device. The optical componentsare integrated as a part of the Processor. The optical signals areguided using the Transmission Structures to the Data Collector andfurther into the tissue through the hydrogel. Herein, numeral 19 refersto a Light shielding on PCB, numeral 20 refers to light shielding ingel, numeral 21 refers to LEDs, numeral 22 refers to photodiodes, andnumeral 23 refers to amplifier circuits.

FIG. 9: The FIG. illustrates a possible integration of the opticalsystem and components in the monitoring device. The optical componentsare integrated as a part of the Data Collector. The Data Collector andProcessor have electrical connections through the TransmissionStructures by conduction silicon wires. Herein, numeral 24 refers to alight shielding, numeral 25 refers to LEDs, numeral 26 refers tophotodiodes, numeral 27 refers to a coin cell battery, and numeral 28refers to amplifier circuits.

The layout and geometry of optical sensor comprising electro opticcomponents of light emitting diodes (LEDs) and photodiodes is seen inFIG. 3. The geometry and separation between the LEDs and photodiodes isessential as this influences the quality of measured photoplethysmograms(PPGs). Preferably, the separation between the LEDs and photodiodesshould be in the range 4 mm to 7 mm.

FIG. 10: The FIG. shows the top view of two layouts of a printed circuitboard with electro optic components of light emitting diodes (LEDs) andphotodiodes. 4-8 photodiodes are mounted in an annular geometry with(LEDs) in the centre. The wavelengths of the LEDs are 660 nm and 940 nm,respectively. The photodiodes are e.g. the BPW34 or similar. Herein,numeral 29 and 30 refer to shielding.

The device may comprise one or more of the following components:

Photodiodes

-   -   High quantum efficiency in the range 390 nm to 1100 nm.    -   Low capacitance per area i.e. max 1 nF/cm2    -   Surface mountable devices    -   The photodiodes size should fit to a circle with a radius of 4        mm to 6 mm from the center to the first edge of the photodiodes    -   The photodiodes should preferably have an antireflection coating        matched to the refractive index of the gel.        Light Emitting Diodes    -   To or more wavelengths in the range 390 nm to 1100 nm,        preferably 660 nm and 940 nm    -   Low optical noise    -   Surface mountable devices.    -   Small form factor approx. 1 mm by 2 mm.        Gels    -   Transparent, e.g. 50% or more of the light with wavelengths in        the range 390 nm to 1100 nm is transmitted per mm gel.    -   Refractive index of in the range of 1.01 to 1.7 (The refractive        index of in vivo tissue is in the range 1.34-1.42 is as        disclosed in Tearney, G. J. et al. “Determination of the        refractive index of highly scattering human tissue by optical        coherence tomography”, Opt Lett, 1995, 20, 2258 and Ding, H. et        al. “Refractive indices of human skin tissues at eight        wavelengths and estimated dispersion relations between 300 and        1600 nm.” Phys Med Biol, vol. 51, no. 6, pp. 1479-1489, March        2006.)    -   Non-conducting gel; if the gel is in contact with conducting        parts of the printed circuit board.    -   Conduction gel if used for electrical contact to the skin.        Amplifier

If a general trans-impedance amplifier is used it should have thefollowing specifications:

-   -   The bandwidth should be compatible with simultaneous        measurements of a 120 Hz sinusoidal oscillating background        light, red PPG, and infrared PPG. E.g. if the signals should be        sampled within a maximum of 1% change of the background light        normalized with respect to the maximum they should be sampled        within 26 μs. It is possible to have a shorter bandwidth if the        sampling frequency is higher than 240 Hz (Nyquist criterion).        The background light signal can then be interpolated. The        bandwidth should further be compatible with a desired rise time        for the photodiodes and amplifier circuit. The rise time        represents excess power consumption by the LEDs. E.g. the        sampling time of the MSP430 is 4 μs. If an excess power        consumption of the LEDs due to the rise time is 1% then the rise        time should be 40 ns, equivalent to a bandwidth of the amplifier        of 8.75 MHz. The CC2430 has a sampling frequency of 160 μs,        applying the same requirement gives a bandwidth of 218 kHz.    -   The operational amplifier should have a low noise. In particular        the flicker noise should be low since the flicker noise is        likely to be in the same band as the PPG signal.    -   The gain/noise ratio should be as high as possible and likely        higher than 109.

Alternatively a switched integrated trans-impedance amplifier can be useto reduce noise by integrating the signal over a time window.

The invention claimed is:
 1. A monitoring device suitable for attachmentto a surface of a subject, the device comprising: a data collector and aprocessor; the data collector comprising: a surface adapted for adhesivecontact with a skin surface of a subject and adapted for receiving aphysiological signal from the skin surface; a transmission structure fortransmitting a monitoring signal which represents the physiologicalsignal to the processor; a body element housing a battery; a detectingcomponent; a base; and an adapter; wherein the adapter forms ananchoring structure and an interface for the processor, the baseattaches the monitoring device to the subject via an adhesive gel, andthe adhesive gel forms a transmission passage for the physiologicalsignal from the subject to the detecting component; the processorcomprising: an electronic circuit; and a gripping structure for holdingthe anchoring structure provided on the data collector; wherein thegripping structure is adapted to destroy the data collector upondetachment of the electronic circuit from the data collector.
 2. Themonitoring device of claim 1, wherein the detecting component comprisesat least one sensor for non-invasive capturing of the physiologicalsignal.
 3. The monitoring device of claim 1, wherein the detectingcomponent comprises at least one sensor for invasive capturing of thephysiological signal.
 4. The monitoring device of claim 1, wherein thedata collector further comprises a data storage.
 5. The monitoringdevice of claim 1, wherein the device further comprises a scheme memorymeans with specific data schemes corresponding to modes of operation;and wherein the data collector further comprises an identification meansconfigured to identify a type of the physiological signal that matchesthe mode of operation.
 6. The monitoring device of claim 1, wherein thedevice further comprises a filter for modifying the physiologicalsignal.
 7. The monitoring device of claim 1, wherein the electroniccircuit comprises wireless communications components.
 8. The monitoringdevice of claim 1, wherein the data collector further comprises anactuator for converting the physiological signal from one form of energyto another form which can act on the skin surface of the subject; andwherein the actuator alerts the subject to a condition based on thephysiological signal received by the data collector.
 9. A method ofmonitoring data based on physiological signals received from a subject,the method comprising: attaching, to a skin surface of a subject, a datacollector capable of detecting a physiological signal and transmitting amonitoring signal which represents the physiological signal to aprocessor; and using the processor, which is attached to the datacollector and comprises an electronic circuit, for processing themonitoring signal; wherein: the data collector includes a detectingcomponent, a base, and an adapter; the adapter forms an anchoringstructure and an interface for the processor, the base attaches themonitoring device to the subject via an adhesive gel, and the adhesivegel forms a transmission passage for the physiological signal from thesubject to the detecting component; the processor includes a grippingstructure; the data collector is attached to the processor by use of thegripping structure cooperating with the anchoring structure on the datacollector; and the gripping structure destroys the data collector upondetachment of the electronic circuit from the data collector.
 10. Themethod of claim 9, wherein the detecting component comprises at leastone sensor for non-invasive capturing of the physiological signal. 11.The method of claim 9, wherein the detecting component comprises atleast one sensor for invasive capturing of the physiological signal. 12.The method of claim 9, wherein the data collector further comprises adata storage.
 13. The method of claim 9, wherein the device furthercomprises a scheme memory means with specific data schemes correspondingto modes of operation; and wherein the data collector further comprisesan identification means configured to identify a type of thephysiological signal that matches the mode of operation.
 14. The methodof claim 9, wherein the device further comprises a filter for modifyingthe physiological signal.
 15. The method of claim 9, wherein theelectronic circuit comprises wireless communications components.
 16. Themethod of claim 9, wherein the data collector further comprises anactuator for converting the physiological signal from one form of energyto another form which can act on the skin surface of the subject; andwherein the actuator alerts the subject to a condition based on thephysiological signal received by the data collector.